Metal coating composition



Patented June 9, 1953 Herschel G, Smith, Wallingtord, Troy L. Cantrell,

Lansdcwne, and .Earl E. Fisher, Yemen, Pg assignors to Gulr Oil Corporation, Pittsburgh,- Pa., a corporation of Pennsylvania No Drawing. Application July 20, 1949, Serial No. 105,902

8 Claims. Cl. 106*14) This invention relates to a metal coating composition and more particularly to a coating composition having a bituminous base and having improved properties for use in coating metal suracest v Metallic parts and materials composedof metal' are subject to oxidation and corrosion upon Storage, especially those containing iron or ferrolls alloys heretofore it has been customary to protect these parts against corrosion by applyi a prot ctiv film such as may be'Droduoed .by grease-like compositions, by plastic compositions such as pyroxylin type films or. by asphalt base varnishes. The grease-like materials have been found unsatisfactory because of their poor resistance to abrasion, melting and other conditions encountered during storage. The asphalt varnishes and plastic coatings ar satisfactory as regards protection against oxidation but these compositions are extremely difficult to remove from the metal surfaces. Furthermore, decomposition of the components of the coating compositions themselves may free acids which react with the metal-containing base to iorm metallic soaps. This is particularly true when, as is often the case, the coating composition contains as an additive a soap of a metal which is replaceable by iron.

An object of our invention is to provide an improved coating composition for use with metallic surfaces which is highly resistant to abra- $1021 and melting, which is highly adhesive, and which is easily removable after long periods of weathering.

It is a further object of our invention to provide an improved coating composition which possesses superior resistance to cracking and checking.

Another object is to provide a composition the constituents of which are resistant to oxidation.

Still another object is to provide a composition which contains therein a material which will inhibit thecorrosive effects of various impurities or decomposition products contained in the composition.

These and other objects are accomplished by the coating composition of our invention which comprises asphalt, microcrystalline wax, and a relatively small amount of a primary fatty amine salt of fl-methylbutyl, Z-ethylhexyl ortho phos- 2 Dhoric acid. A filler and a resinous material act,- ing as a plasticizer may be added if, desir d- A common solvent for all materials except the filler may be employed to produce a liquid composition.

Typical. turin cations Blown Asphalt {Test when Blown to Melting Pour F., Bing on B 200, 200

A typical microcrystalline wax which maybe used in our invention conforms'to the following specifications:

Manufactur- Test mg Specifications 4 Gravity; Liguid.State,API, Theor 34.6...." I I Mglgli gslgomt, F., Petrolatum. ASTM 163 (160-170). Penetration, ASTM 13217-441". 77 r.,15 1o (3., 5 Sec., Unworked. Pzgnesetration, ASTM D5 25, 77 F., 200 G., 40 (Mair. 50). 80 I Viscosity, SUV, 210 F- 7l.5. ('75); Flash, P-M, F ms (Min. 50o).

Flash, 00

int Color, Solid Stat Appearance (Maxilll). Neu raliz tion No .1

Iodine No., Mod. Hands (Max. 71)).

1 Greenishbrown. Smooth (smooth, not greasy).

other microcrystalliuc. waxes, may

3 which have melting points varying from about 100 F. to about 300 F. The function of the wax is that it acts as a plasticizer for the asphalt, thus producing a more pliable product.

A corrosion inhibitor comprising a primary fatty amine salt which is the substantially neutral addition product of 3-methylbutyl, 2-ethylhexyl ortho phosphoric acid and a primary fatty amine having from 8 to 18 carbon atoms, and which may be prepared according to the method set forth i'n'Unit'd States Patent 2,387,537,'-'issued October'23; 1945, to Herschel G. Smith and Troy L. Cantrell, is also employed in our composition.

This substance has a two-fold function. First,

it is specific as a corrosion inhibitorandprevents any corrosive impurities in the coating composition from attacking the inetal surface."

We have also found that thi's 'compositiomwhen incorporated in the composition of ourinvention, produces the unexpected result of'preventing gelling of the composition and also that of reducing its viscosity, thus enabling the compoj-i sition to be more easily applied.

The preferred aspect of our invention involves the use of a common solvent to dissolve all of the components of our composition or to form a liquid composition. One suitable solvent is stod dard solvent. However, other light hydrocarbon solvents, such as gasoline, may be employed. In fact any easily volatile solvent which will dissolve the ingredients of'our composition sulficiently to form a relatively uniform liquid mix ture may be employed. Some further" examples of satisfactory solvents areturpentine and similar terpene type solvents, mixtures of aliphat'id'a'romatic, and naphthenic" type hydrocarbons, mixtures'of higher alcohols and hydrocar'bons, and mixtures of ketones and hydrocarbcnsi In 'c'er tain individual cases ketones and alcohols may be employedas the solvent. However; in general we prefer to use these in conjunction with hy'- drocarbon solvents. T a

An optional vingredient which may be included in our composition is a low molecular weight resinous compound. The resinous material when utilized in our.invention also has as its function that of plasticizer for the asphalt. The addition of the resin to the asphalt-wax mixture produces a rubberelike' composition. The resinous material is one selected from the group consisting of hydrogenated rosin, rosin and coumarone indene resin. I

The coumarone indene resin which is useful for this purpose possesses excellent solubility in naphtha base petroleum solvents. This material is polymeric in form and is thought to'be a chain structure having one terminal double bond per mol. However, there is some evidence to indicate that the structuremight be-cyclic. A satisfactory coumarone indene resin for our invention has the following properties:

A suitable hydrogenated rosin for use in our coating composition is sold under the name of Staybellite and has the following properties:

4 Melting point: F.

Dropping method 165-175 Saturation: per cent by weight min. 60

Rosin or colophony useful in this invention has Another component which may be included in our composition when desired is a finely comminuted filler. The functions of this material are inert fillers suchas titanium dioxide or various other conventional paint pigments may be em- 1 ployed with equal facility. The particles of filler are desirably of a size less than about 150 mesh; .Inpreparing our composition for use, the individual components may be added in any order.

When a solvent is used the components may be dissolved in the solvent at room temperature- If desired, the mixture may be heatedfto a temperature above about F., depending upon the particular solvent used, in order to hasten melting or solution. .Any temperature between room temperature and decomposition tempera ture may be used. 01: course, ifa solvent is not used in preparing the composition, the minimum temperature would bethat necessary to cau'se melting and uniform intermixture.

Our improvedcomposition, in, a preferred vem-j bodiment, is made up of the following. ins'rledi; ents: 1 (1) A blown asphalt such as grade B asphalt of from 15 to 30 per cent- Y.

(2) A high melting point amorphous or microcrystalline wax of from 5 to 10 per cent. I (3) A filler, such as aluminum, mica, graphite, titanium dioxide, or the usual paint pigments of from 0 to 25.per cent. a

(4,) A resinous material selected from the group consisting of hydrogenated rosin, coumarcneindeneresin and rosin of from 0 to 10 per cent.

(5) A relatively volatile naphtha base solvent, such as Stoddard solvent, of from 44.130 60 per cent. (6) A substantially neutral addition product of 3-methylbutyl, 2-ethylhexyl ortho phosphoric acid and a primary fatty amine having 8 to 18 carbon atoms which may be prepared according to the method set forth in U. S. Patent 2,387,- 537, issued October 23, 1945 to Herschel G. Smith and Troy L. Cantrell in amounts varying from about 0.01 per cent to 2 per cent.

Specific examples of my composition are as follows: Example I Make-up: per cent by weight Grade B asphalt 17.5 Petrowax B 7.0 Coumarone indene resin 7.0 Dodecyl amine ,salt of. 3-methylbutyl,

2-ethylhexyl ortho, phosphoric acid 0.5 Aluminum powder 14.0 Stoddard solvent 54.0

g A metallic panel was coated with the-composition described aboveand the coating allowed to dry. The coated panel was then subjected to the conditions .in a humidity cabinet: and, ,;a

weatherometer.

weathemmeter. miolloutns wi s w re o1:- served:

li I, Solubility after Weath mmete Exposure 'verysolublc very soluble.

"' Hydrogenated rosin furnished by vHercules Powder Co.

A metallic panel was coated with the composition described above and the coating allowed to dry. The coated panel was then subjected to the conditions in a humidity cabinet and a weatherometer. The following resuits were observed:

Inspection: 7 J

' Humidity cabinet test $1.

relative humidity at 120 F.)

AN-H31- Panel No .j Ifosit'ion Time of test (days) Result Weatherometer- Solubility after Weatherumeter verysoluble.

Exposure.

Examplell! Make-up: per .cent by weight Grade B asphalt 17,5 Petrowax .B 7.10 Amber rosin"; 7.0 'Dodecyl amine salt of .Zi-methylbutyl,

Z-ethylhexyl ortho phosphoric acid" 0.5

Aluminum powder. 14.0 Stoddard solvent 154.0

A metallic panel was coated with the composition described above and the coating allowed to dry. The coated panel was then subjected to the conditions in a humidity cabinet and a The following result were observed: 7

Humidity cabinet test (100% relative humldlty at 120 F.)

AN HeBL- Time; length omen-(days) Result Woatherometer- Panel No Res Solubility Exposure.

: are thus applied at fixed nitensities.

I 6 -Ecemole I Make-up: per cent-"by w i ht Grade B as phalt w r e 15.35 v Petrowax ,B ,g 6.1 5 5 CDumarene indene resin w c -1 Dodeoyl aunine salt of B-methylbutyl, Z-ethylhexyl ortho phosphoric acid- 0.45 Mica 24.55 M Stoddard solvent 47.35

A metallic panel was coated with the composit-ion described above and the coating allowed to dry. -'Ihe coated panel was then subjected to the conditions in a humidity cabinet and a .1 wea-therometer, The following results were .ob

served:

Inspe tion: 1

Humidity cabinet test (100% relative humidity at 120 F.) ANT Em .Ranel 65.4 Position Timleitlength of test (days) 4 m .65 Weatherometer- I 7 P0siti0n.-.-,.-

'Time, length of test (his) Resul n. Solubility after Weatherorneter Exposure verysoluble; very soluble.

130 xample V 'Makemp: per cent by weight Grade B asphalt 17:5 Petrowax B "7.0 Coumarone indene resin l- 7.0 'Dodeeyl "amine salt of 3-meth-ylbutyl.

Z-ethylheicyl ortho phosphoric acid 0.5 'Gra'phite l 14.0 Stoddard solvent 54:0

40 A metallic panel was coated. With the composition described above and the coating allowed to dry. The coated Panel was then .subjectedto the comiiliions in ,a humidity cabinet and a Weather- .Ometer. The following results were observed:

inspection: 1

Humidity cabinet test relative humidity at AiN'fH 31 Panel N0 1"a"rTo" I 15 0 55 37 .50 n ifit WeathemmeterfanelNo. 'Positiom. Tnnaflongth est Y..-'--.-(-'- F e Solubility after Weatherometer 55 Errposnreuusunusuu. very soluble very soluble.

The Humidity Cabinet Corrosion Test produces amoisture saturated atmosphere of 120 F., with continuous condensation on the test specimens and is used for testing coating materials intended as corrosion preventives. This cabinet was designed to meet the requirements of Army- Navy Aeronautical Standard Specification No. ANAL-311.

The weatherometer used was a National Carbon Weathering Unit Model No'X-l-A. It is designed for exposing test samples :to artificial sunlight or intense ultra-violet radiation under accurately controlled conditions. The source of radiation is a carbon are lamp, about which the test samples are slowly carried during the test. Two spray nozzles permit the sample to be wet during a part of each revolution. The combined Weathering effects of water, air, and thermal shock "The air temperature in the 'weatherorneter on the side opposite the spray is .approximately 116 F. The

rack on which the specimens are hung rotates once in two hours. During this rotation, each specimen is sprayed minutes with fresh water.

It should be noted in connection with the results obtained in the weatherom'eter tests that most conventional asphalt base coating compositions fail after about 10 hours under these conditions and that virtually all of them fail before about 100 hours.

temperatures, as shown in knee-action coil springs.

8. May be applied by brushing, dipping or spraying.

9. Repairs are easily made to assembled mechanisms which have been preserved with these coatings.

10. Coating prevents rusting of bolt threads. and in addition is easily removedbecause of the lubricating properties of the composition.

11. Coating remains naphtha-soluble after weathering.

A suitable method of utilizing the composition of our invention is as follows:

The metal surface to be coated should first be cleaned to remove surface impurities such as pickling by-products, finger prints, or traces of other moisture absorbing films. The cleaning may be carried out in any conventional manner known to the art, such as by swabbing with an alcohol or naphtha solvent. The coating material may then be applied by brushing, dipping or spraying, the viscosity of the compositio having been varied to suit the particular method by controlling the amount of solvent addeda While we have described the preferred form of our invention as involving a liquid solution, it will be clear from the foregoing that we also contemplate a composition prepared without the use of a solvent. Such a composition is desirable since the difficulties attending the shipment of liquids may be avoided. While we have described microcrystalline wax as particularly useful in connection with our invention, any other wax which has its functional properties may be used. Similarly our invention is not limited to the use of Stoddard solvent. Any relatively volatile solvent of the type listed above, which is acommon solvent for th materials of ourxcomposition, may be employed, The specific percentage range for the corrosion inhibitor is merely preferred and is not to be considered limiting, since in certain instances an amount less than 0.01% may be employed, Also an amount greater than 2.0% may be employed but the advantages thus produced do not warrant any substantial increase above 2.0%. i

The coating composition described herein may be used to protect metal surfaces of metal parts which-are to he 'storedi before' using-s By use of our composition the parts may be maintained in their condition as prepared for an indefinite period of; time. Because of the ease of removal of our improved composition the protective coating may {be removed whenever desired with a minimum amount of work.

These coatings have also found particular utility as automobile undercoatings. In this particular application they have been subjected for long periods of time to both summer and winter weather conditions. When employed in this mannerthesecompositions have provided excellent protection to the metalsurfaces so coated and were easily removed for repair of the automobile parts after such long periods of time.

One advantage of our'invention is thegproyision of a protective filmwhich-is highly adhesive to metal and has excellent weathering-characteristics for minimum film thickness atboth high and low temperatures. Another advantage of ourycomposition is that it provides excellent resistance to abrasion, corrosion and-weathering.

Still another advantage of the composition is that. it produces a marked improvement in .resistance to checking and cracking. A further advantage is that the coating material remains easily soluble in light hydrocarbon solvents after long periodsof weathering. A still further advantage is that the composition dries quickly, .i; e., in about four hours.

' the group consisting of hydrogenated rosin, rosin and coumarone indene resin.

3. A liquid coating composition of the class described consisting essentially of from about 15 to 30 per cent blown asphalt, about 5 to 10 per .cent microcrystalline wax, up to 25 per cent filler,

up to'10 per 'cent of a low molecular weight resinous material selected from ,the group consisting of hydrogenated ros'in', rosin and couma rone indene resin 0.01 to 2per cent of a primary fatty amine salt of 3-methylbutyl, Z-ethylhexyl orthophosphoric acid, and. a solvent.

4. A composition in accordance with claim 3, wherein the -resinous materialis hydrogenated rosin. i I

5. A composition vinaccordance with claim 3, wherein the resinous material. is rosin.

6. A composition in accordance with claim 3, wherein the resinous material is a coumarone indene resin.

7. A composition in accordance with claim 3, wherein the solvent is a hydrocarbon-containing solvent,

8. A- liquid coating composition containing the following constituents in approximately the fol lowing percentage proportions:

Blown" asphalt 17.5 Microcrystalline wax 7.0 Low molecular weight resin 7.0 Dodecylamine salt of B-methylbutyl, 2-ethyl- -hexyl orthophosphoric acid. 0.5

9 10 Aluminum powder 14.0 References Cited in the file of this patent Stoddard solvent 54.0 UNITED STATES PATENTS said low molecular Weight resin being selected Number Name Date from the group consisting of hydrogenated rosin, 5 ,5 Sm1 th Oct. 23, 1945 rosin and coumarone indene resin. 2,435,321 0 6 8161 Oct- 3, 1949 2,492,848 Crouch et a1 Dec. 27, 1949 TROY L. CANTREIL. EARL E FISHER 10 Number Country Date 7' 604,408 Great Britain July 2, 1948 

3. A LIQUID COATING COMPOSITION OF THE CLASS DESERIBED CONSISTING ESSENTIALLY OF FROM ABOUT 15 TO 30 PER CENT BLOW ASPHALT, ABOUT 5 TO 20 PER CENT MICROCRYSTALLINE WAX, UP TO 25 PER CENT FILLER, UP TO 10 PER CENT OF A LOW MOLECULAR WEIGHT RESINOUS MATERIAL SELECTED FROM THE GROUP CONSISTING OF HYDROGENATED ROSIN, ROSIN AND COUMARONE INDENE RESIN 0.01 TO 2 PER CENT OF PRIMARY FATTY AMINE SALT OF 3-METHYLBUTYL, 2-ETHYHEXYL ORTHOPHOSPHORIC ACID, AND A SOLVENT. 